Precision optical tabletop

Abstract

A precision tabletop for scientific instrumentation is described. The tabletop may be manufactured from as few as two pieces of material, include a honeycomb stiffening and vibration damping structure, be sealed from fluid ingress, include interior reinforcing structures, and permit accurate registration of machined features on all sides of the tabletop.

The invention claimed is: 
     
       1. A precision tabletop comprising:
 a top body having a top surface and a bottom surface; 
 a honeycomb structure having honeycomb cells located in the top body below the top surface; 
 a solid region formed in the top body and located within the honeycomb structure, wherein the solid region fills a volume that is greater than a volume of a cell of the honeycomb structure and extends from the top surface to the bottom surface of the top body; 
 a first machined feature formed on the bottom surface of the solid region that is registered to at least one machined feature formed on the top surface of the top body; 
 backing regions at first intersections of ribs in the honeycomb structure; and 
 blind holes formed in the backing regions. 
 
     
     
       2. The precision tabletop of  claim 1 , wherein the honeycomb structure and the solid region are formed into a same piece of material used to make the top body. 
     
     
       3. The precision tabletop of  claim 1 , further comprising a second machined feature formed on a side of the top body that is registered to one or more machined features formed on the top surface of the top body. 
     
     
       4. The precision tabletop of  claim 1 , wherein the top body is formed from a metal. 
     
     
       5. The precision tabletop of  claim 1 , wherein the honeycomb structure extends across at least one-quarter of a total area of the top body. 
     
     
       6. The precision tabletop of  claim 1 , wherein the honeycomb cells have different sizes and/or shapes in different regions of the top body. 
     
     
       7. The precision tabletop of  claim 1 , wherein ribs of the honeycomb cells have different thicknesses in different regions of the top body. 
     
     
       8. The precision tabletop of  claim 1 , further comprising one or more bottom plates adhered over the honeycomb structure. 
     
     
       9. The precision tabletop of  claim 8 , further comprising bonding expansions at one or more second intersections of the ribs in the honeycomb structure to which the one or more bottom plates are adhered. 
     
     
       10. The precision tabletop of  claim 1 , wherein the bottom surface of the solid region is parallel to the top surface of the top body to within ±0.01 radians. 
     
     
       11. A method of forming a precision tabletop, the method comprising:
 forming a honeycomb structure in at least one region of a top body core, wherein the honeycomb structure is formed below a top surface of the top body core; 
 leaving a solid region spanning multiple honeycomb cell widths within the honeycomb structure; 
 machining first features on the top surface of the top body core; and 
 aligning and machining second features on a bottom surface of the solid region to be registered to at least one machined feature on the top surface. 
 
     
     
       12. The method of  claim 11 , wherein forming the honeycomb structure comprises forming backing regions at intersections of ribs of the honeycomb structure, and further comprising forming blind holes in the backing regions. 
     
     
       13. The method of  claim 11 , wherein forming the honeycomb structure comprises forming bonding expansions at intersections of ribs of the honeycomb structure, and further comprising adhering a bottom plate to the bonding expansions. 
     
     
       14. The method of  claim 11 , further comprising machining the bottom surface of the solid region to be parallel to the top surface within ±0.01 radians. 
     
     
       15. The method of  claim 11 , further comprising aligning and machining third features on a side surface to be registered to at least one machined feature on the top surface. 
     
     
       16. A precision tabletop comprising:
 a top body having a top surface and a bottom surface; 
 a honeycomb structure having honeycomb cells located in the top body below the top surface; 
 a solid region formed in the top body and located within the honeycomb structure, wherein the solid region fills a volume that is greater than a volume of a cell of the honeycomb structure and extends from the top surface to the bottom surface of the top body; 
 a first machined feature formed on the bottom surface of the solid region that is registered to at least one machined feature formed on the top surface of the top body; and 
 a second machined feature formed on a side of the top body that is registered to at least one machined feature formed on the top surface of the top body. 
 
     
     
       17. The precision tabletop of  claim 16 , wherein the honeycomb structure and the solid region are formed into a same piece of material used to make the top body. 
     
     
       18. The precision tabletop of  claim 16 , wherein the honeycomb cells have different sizes and/or shapes in different regions of the top body. 
     
     
       19. The precision tabletop of  claim 16 , further comprising bonding expansions at intersections of ribs in the honeycomb structure. 
     
     
       20. The precision tabletop of  claim 16 , wherein the bottom surface of the solid region is parallel to the top surface of the top body to within ±0.01 radians.